FR2794116A1 - ZEOLITHE IM-5 WITH PHOSPHORUS, CATALYTIC COMPOSITION, ITS PREPARATION AND ITS USE IN CATALYTIC CRACKING - Google Patents

Abstract

An IM-5 zeolite modified by adding phosphorus, optionally dealuminated, preferably in aluminosilicon form, containing at most 10% by weight of phosphorus, is described, a composition containing it, its preparation processes and its application to the catalytic cracking of hydrocarbon feedstocks. .

Description

The present invention relates to a zeolite called IM-5 modified in

  adding phosphorus, optionally free of metal Ti, B, Fe, Ga or AI, a catalytic composition containing it, its preparation and its use in particular in a process for catalytic cracking of a hydrocarbon feedstock. More specifically, it relates to an aluminosilicate molecular sieve stabilized with at least one phosphorus compound. Molecular sieves of a zeolitic nature are crystalline materials comprising a three-dimensional network of tetrahedra T'04 with T 'equal to Si, AI, B, P, Ge, Ti, Ga, Fe, for example. This network defines an intracrystalline microporous network of dimensions comparable to those of small to medium organic molecules. The microporous network can be a system of channels and / or cavities, shaped by the crystal network, which can be identified by its specific and specific X-ray diffraction diagram. The potential applications of a zeolite (for example, in the catalysis, adsorption, cation exchange and purification processes) mainly depend on the size, shape and characteristics (mono-, multidimensional) of its microporous network and its chemical composition. For example, in aluminosilicate zeolites, the presence of A104- tetrahedra isolated in a matrix of SiO4 tetrahedra requires the presence of compensating cations to counterbalance the negative charge of the network. Typically, these cations have a high mobility and can be exchanged by others, for example H + or NH4 +, the latter being able to be transformed into H + by calcination, which leads to an acid microporous solid. The zeolite is then in its acid form also called hydrogen form. When all the compensating cations are organic ammonium or alkylammonium cations, the calcination leads directly to the acid form of the zeolite. These microporous acid solids can be used in acid catalysis processes and their activity and selectivity depend both on the strength of the acid, on the density of the acid sites, on the dimensional characteristics of

  the space delimited in the network where the acid sites are located.

  The size of the channels can be described by the number of T'04 tetrahedra present in

  the ring delimiting the pore openings, element which controls the diffusion of the molecules.

  Thus, the channels are classified in categories: small pores (openings of annular pores delimited by a sequence of 8 tetrahedrons T'04 (8 MR), medium pores (10 MR) and large pores (12 MR), MR wanting "membered ring" in English. This structural characteristic can provide interesting shape selectivity properties to these materials in heterogeneous catalysis. The term shape selectivity is generally used to explain specific catalytic selectivities due to steric constraints which exist inside the zeolitic microporous system. These constraints can act on the reagents (diffusion of the reagents in the zeolite), on the reaction products (formation and diffusion of the products formed outside the zeolite) on the reaction intermediates or on the reaction transition states which form in the microporosity of the zeolite during the reactions. The presence of con appropriate steric tracings makes it possible in certain cases to avoid the formation of transition states and reaction intermediates leading to the formation of undesirable products and improves

  in some cases selectivities.

  The object of the invention relates to the IM-5 zeolite, optionally partially devoid of metal T, containing phosphorus and its use when it is partly desaluminated in catalytic cracking, alone or in mixture with a conventional catalytic cracking catalyst. . The catalyst of the present invention is particularly well suited to cracking petroleum fractions in order to produce a large quantity of compounds having 3 and / or 4 carbon atoms per molecule and more particularly propylene and butenes. The catalyst of the present invention is particularly well suited to cracking

heavy petroleum fractions.

  The present invention also relates to the process for cracking heavy petroleum charges, in the presence of the catalyst defined above, as well as the processes for preparing said catalyst. The cracking of hydrocarbon charges, making it possible to obtain high yields of gasoline for very good quality automobiles, became essential in the petroleum industry from the end of the 1930s. The introduction of processes operating in a fluid bed (FCC or Fluid Catalytic Cracking) or in a moving bed (such as TCC) in which the catalyst circulates permanently between the reaction zone and the regenerator where it is freed from coke by combustion in the presence of a gas containing oxygen, introduced

  significant progress compared to the fixed bed technique.

  The catalysts most used in cracking units since the early 1960s are zeolites usually of faujasite structure (FAU). These zeolites, incorporated in an amorphous matrix, for example consisting of amorphous silica-alumina, and which may contain variable proportions of clays, are characterized by crunchy activities,

  with respect to hydrocarbons, 1,000 to 10,000 times greater than those of silica catalysts

  alumina rich in silica used until the late 1950s.

  In the late 1970s, the lack of availability of crude oil and the growing demand for high-octane gasoline led refiners to process heavier and heavier crudes. The treatment of the latter constitutes a difficult problem for the refiner because of their high content of catalyst poisons, in particular of metal compounds (in particular nickel and vanadium), values which are unusual in

  Conradson carbon and especially in asphaltenic compounds.

  This need to deal with heavy loads and other more recent problems, such as the progressive but general elimination in the essence of lead-based additives, the slow but noticeable evolution in certain countries of the demand for middle distillates (kerosene and diesel fuels), have also encouraged refiners to look for improved catalysts which make it possible to achieve the following objectives in particular: - better thermal and hydrothermal stability and better tolerance to metals, lower production of coke with identical conversion, - better octane number gasoline,

  - improved selectivity in middle distillates.

  In the majority of cases, it is sought to minimize the production of light gases, comprising compounds having from 1 to 4 carbon atoms per molecule, and, consequently, the

  catalysts are designed to limit the production of such light gases.

  However, in certain particular cases there appears to be a significant demand for light hydrocarbons of 2 to 4 carbon atoms per molecule or in some of them, such as

  as C3 and / or C4 hydrocarbons and more particularly propylene and butenes.

  Obtaining a large quantity of butenes is particularly advantageous in the case where the refiner has an alkylation unit, for example C3-C4 cuts containing

  olefins to form an additional amount of high octane gasoline.

  Thus the overall yield of good quality gasoline obtained from the cuts

  starting oil is significantly increased.

  Obtaining propylene is particularly desired in certain developing countries.

  development, where there is a significant demand for this product.

  The catalytic cracking process can meet such demands to a certain extent, provided in particular that the catalyst is adapted for this production. An effective way to adapt the catalyst consists in adding to the catalytic masses an active agent having the following two qualities: - cracking heavy molecules with good selectivity in hydrocarbons with 3 and / or 4 carbon atoms, in particular in propylene and in butenes ; - be sufficiently resistant to the severe conditions of partial steam pressure and

  of temperature prevailing in the regenerator of an industrial cracker.

  The research carried out by the applicant on numerous zeolites led him to discover that, surprisingly, the zeolite called IM-5 and modified by adding phosphorus called IM5-P, made it possible to obtain a catalyst having an excellent activity and having good selectivity with respect to the production of hydrocarbons with 3 and / or 4 carbon atoms per molecule. The use of such a zeolite according to the invention makes it possible to obtain a cracking catalyst leading to the obtaining of a larger proportion of gas, and in particular of propylene and butenes. The phosphorus content of the IM5-P zeolite is generally at most equal to 10% by weight, advantageously at most equal to 5%, expressed by weight, for example between

2 and 4%.

  The invention also relates to the process for the preparation of the IM-5 zeolite modified in

adding phosphorus.

  Phosphorus can be added at various times: in the presence of a structuring agent, directly during synthesis, in solution and this in various chemical forms: phosphoric acids, phosphates, organophosphates, phosphorus chlorides. More precisely, according to a first variant, the IM5-P zeolite is prepared by bringing into contact at least one nitrogenous organic cation, at least one silicon or germanium oxide, at least one metal oxide T chosen from the group formed by AI , Fe, Ga Ti and B and at least one phosphorus compound and optionally an alkali metal oxide M and / or ammonium, or their precursors, the mixture generally having the following molar composition XO2 / T203 at least 10, (RII.) OH / XO2 from O, 01 to 2 H2O / XO2 from I to 500 Q / XO2 from 0.005 to 1 LqZO2 from 0 to 5 o X is silicon and / or germanium, T is chosen from the group formed by the following elements : aluminum, iron, gallium, titanium and boron R is a cation of valence n which contains M (an alkali metal cation and / or ammonium), and / or Q (a nitrogenous organic cation or a precursor thereof) ci or a decomposition product thereof), and LqZ is a salt, Z being an anion of valence q and L, an alkali metal ion or ammonium which may be similar to M or a mixture of M and another alkali metal ion or an ammonium ion necessary to balance the anion Z, Z which may contain an acid radical

  added for example in the form of an L salt or an aluminum salt.

  Preferably, X can be silicon and Y can be aluminum.

  According to a second preferred variant, it is possible to impregnate, under suitable conditions, the IM-5 zeolite optionally calcined, with an aqueous solution of at least one acid chosen from the group formed by H3PO3 (NH4) 3PO4, (NH4) 2H PO4 , (NH4) H2PO4 or one of its salts. The product obtained is generally calcined at a temperature of 350 to 1000 ° C. for a period depending on the calcination temperature used, which can vary from 0.1

second at 10 o'clock for example.

  These two modes of implementation are particularly advantageous since the absence of alkaline ions avoids at least one step of ion exchange, by an ion solution.

  ammonium for example and a calcination step to obtain the acid form.

  The IM5S-P zeolite at least partially in hydrogen form according to the present invention has a structure which has not yet been elucidated but which is identical to that of the

  IM5 zeolite without phosphorus described in French patent application FR-2,754,809.

  The IM-5-P zeolite, in synthetic raw form, is characterized by the fact that it has

  an X-ray diffraction diagram comprising the lines presented in table 1.

  The zeolite IM-5-P in its hydrogen form, designated H-IM-5-P, is obtained by calcination (s) presents an X-ray diffraction diagram comprising the lines

presented in Table 2.

  Table 1: X-ray diffraction table for the zeolite IM-5-P dhkl () "Imax

11.8 +0.35 F at TF (I)

11.5 + 0.30 F at TF (I)

11.25 +0.30 Fto TF ()

  9.95 + 0.20 m at F 9.50 + 0.15 m at F 7.08 + 0.12 f to m 6.04 + 0.10 tf at f, 75 + 0.10 f, 65 + 0 , 10 f, 50 + 0.10 tf, 35 + 0.10 tf, 03 +0.09 tf 4.72 + 0.08 f to m 4.55 + 0.07 f 4.26 + 0.07 tf

3.92 +0.07 F to TF (2)

3.94 +0.07 TF (2)

3.85 + 0.05 TF (2)

3.78 + 0.04 F at TF (2)

  3.67 +0.04 m at F 3.55 + 0.03 m at F 3.37 + 0.02 f 3.30 + 0.015 f 3.099 + 0.012 f at m 2.970 +0.007 tf to f 2.815 0.005 tf 2.720 +0.005 tf

  (1) Rays forming part of the same massif, (2) Rays forming part of the same massif.

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  Table 2 X-ray diffraction table for the H-IM-5-P dhkl () zeolite I / Imax

11.8 + 0.30 F at TF (I)

11.45 + 0.25 TF (I)

11.20 + 0.20 F at TF (I)

  9.90 + 0.15 m at F 9.50 + 0.15 m at F 7.06 + 0.12 f at m 6, 01 + 0.10 tf at f, 70 + 0.10 f, 30 + 0, 10 tf, 03 + 0.09 tf 4.71 + 0.08 f 4.25 + 0.07 tf 3.87 + 0.07 m at F (2) 3.81 0.05 m at F (2) 3.76 0.04 m at F (2) 3.67 + 0.04 f to m 3.54 + 0.04 m at F 3.37 + 0.03 f 3.316 + 0.015 f 3.103 + 0.012 f 3.080 + 0.010 f to m 2.950 + 0.010 tf to f 2.880 + 0.007 tf 2.790 +0.005 tf 2.590 + 0.005 tf

  (1) Rays forming part of the same massif, (2) Rays forming part of the same massif.

  These diagrams are obtained using a diffractometer using the conventional method of powders with the Ka radiation of copper. From the position of the diffraction peaks represented by the angle 20, we calculate, by the Bragg relation, the reticular equidistances dhkl characteristic of the sample. The intensity is calculated on the basis of a relative intensity scale on which a value of 100 is assigned to the line with the highest intensity on the X-ray diffraction diagram: * very low (tf) means less than 10, * weak (f) means less than 20 * medium (m) means between 20 and 40, * strong (F) means between 40 and 60,

  At very high (TF) means greater than 60.

  The X-ray diffractograms from which these data were obtained (spacing d and relative intensities) are characterized by broad reflections with numerous peaks forming shoulders on other peaks of higher intensity. It may happen that some or all of the shoulders are not resolved. This can happen for weakly crystalline samples or samples in which the crystals are small enough to give a significant broadening of the X-rays. This can also be the case when the equipment or conditions used to obtain the

  diagram differ from those used here.

  The IM-5 zeolite, in hydrogen form, designated by H-IM-5 and obtained by calcination and / or ion exchange of the crude synthetic IM-5 zeolite, used in the process

  according to the invention as well as its mode of synthesis are described in the patent application FR-

2.754.809.

  The zeolitic structure, called IM-5, has a chemical composition, expressed on an anhydrous basis, in terms of molar ratios of oxides, by the formula: X02, mT20l, p R2 / nO, om is equal to or less than 10, p is between O (excluded) and 20,

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  R represents one or more cations of valence n, X is silicon and / or germanium, preferably silicon, T is chosen from the group formed by the following elements: aluminum, iron, gallium,

  boron, titanium, preferably T is aluminum.

  The IM-5-P zeolitic structure according to the invention has substantially the same chemical composition. The IM-5-P zeolite has an Si / T atomic ratio of between 5 and 600 and in

1 0 particular between 10 and 300.

  The overall Si / T ratio of the zeolite and the chemical composition of the samples are

  determined by X-ray fluorescence and atomic adsorption.

  The IM-5-P zeolite according to the invention can be obtained with the desired Si / T ratio, for the catalytic application according to the invention, directly to the synthesis by adjusting the synthesis operating conditions. Then the zeolite is calcined and exchanged by at least one treatment with a solution of at least one ammonium salt so as to obtain the form

  ammonium from the zeolite which once calcined leads to the hydrogen form of the zeolite.

  Furthermore, certain catalytic applications require an adjustment of the thermal stability and the acidity of the zeolite to the envisaged reaction. One of the ways to optimize the acidity of a zeolite is to reduce the amount of metal T present in its frame. The Si / T ratio of the framework can be adjusted during synthesis or after synthesis. In the latter case, the so-called metal removal operation must in particular be carried out while destroying the crystal structure of the zeolite as little as possible. It is thus possible to have a zeolite whose atomic Si / T ratio can be between 5 and

  600 and whose acidity can be controlled.

  It is known to those skilled in the art that a partial dealumination of the structure of the zeolite and more generally the partial elimination of the metal T results in a thermally more stable solid 11. However, dealumination treatments which zeolites undergo lead to the formation of extra-structural aluminum species which can obstruct the microporosity of the zeolite if they are not eliminated. This is for example the case of zeolites used as additives to the catalytic cracking catalyst in FCC units, for the production of olefins. Indeed, in the regenerator of the cracking unit reign high temperatures, above 600 C, and a significant water vapor pressure which will lead to dealumination of the structure of the zeolites and consequently to a loss of acidic sites and clogging of microporosity. These two phenomena contribute to a decrease in the activity therefore of the effectiveness of the additive

1 0 zeolitic.

  On the other hand, a controlled dealumination carried out outside the unit makes it possible to exactly regulate the dealumination rate of the framework of the zeolite and also makes it possible to eliminate in particular the extra-framework aluminum species which obstruct the microporosity unlike what happens in the 'cracking unit, as explained in the previous paragraph. The step of partial elimination of the metal and in particular of post-synthesis dealumination can be carried out by any technique known to those skilled in the art; non-limiting examples which may be mentioned are any heat treatment, optionally in the presence of water vapor, followed by at least one acid attack with at least one solution of a mineral or organic acid, or else any dealumination by at minus an acid attack with at least one solution of a mineral or organic acid. This elimination of the metal leads to IM-5-P phosphorous zeolites whose Si / T atomic ratio is greater than 5, advantageously greater than 10, preferably greater than 15 and more particularly between 20 and 400, which gives both activity and resistance to

zeolite according to the invention.

  According to a first variant of the metal elimination step, the first method known as direct acid attack comprises a first calcination step under a flow of dry area, at a temperature generally between approximately 450 and 550 ° C., which aims to remove the organic structuring present in the microporosity of the zeolite, followed by a step of treatment with an aqueous solution of a mineral acid such as HNO3 or HCl or organic such as CH3COH. This last step can be repeated as many times as necessary in order to obtain the desired dealumination level. Between these two stages, it is possible to carry out one or more ion exchanges with at least one NH4NO3 solution, so as to eliminate at least in part, preferably practically completely, the alkaline cation, in particular sodium. Similarly, at the end of the dealumination treatment by direct acid attack, it is possible to carry out one or more ionic exchanges with at least one NH4NO3 solution, so as to remove the residual alkaline cations and in

especially sodium.

  To achieve the desired Si / AI ratio, for example, it is necessary to choose the operating conditions well; from this point of view the most critical parameters are the temperature of the treatment with the aqueous acid solution, the concentration of the latter, its nature, the ratio between the amount of acid solution and the mass of zeolite treated, the duration

  of treatment and the number of treatments performed.

  - According to a second variant of the metal elimination step, the second method called thermal treatment (in particular with steam or "steaming") + acid attack, comprises, firstly, calcination under dry air flow, at a temperature generally between about 450 and 550 C, which aims to eliminate the organic structuring agent occluded in the microporosity of the zeolite. Then the solid thus obtained is subjected to one or more ionic exchanges by at least one NH4NO solution, so as to eliminate at least in part, preferably practically completely, the alkaline cation, in particular the sodium, present in the cationic position in the zeolite. . The zeolite thus obtained is subjected to at least one structural dealumination cycle, comprising at least one heat treatment carried out, optionally and preferably in the presence of steam, at a temperature generally between 500 and 900 ° C., and optionally followed at least one acid attack with an aqueous solution of a mineral or organic acid. The calcination conditions in the presence of water vapor (temperature, water vapor pressure and duration of treatment) as well as the post-calcination acid attack conditions (duration of attack, acid concentration, nature of the acid used and the ratio between the volume of acid and the mass of zeolite), are adapted so as to obtain

1 3 2794116

  the desired dealumination level. For the same purpose we can also play on the number

  of heat treatment-acid attack cycles which are carried out.

  In the preferred case where T is AI, the dealumination cycle of the frame, comprising at least one heat treatment step, optionally and preferably carried out in the presence of water vapor, and at least one attack step in an acid medium. of the IM-5 zeolite, can be repeated as many times as necessary to obtain the dealuminated IM-5 zeolite having the desired characteristics. Similarly, following the heat treatment, possibly carried out and preferably in the presence of water vapor, several successive acid attacks, with acid solutions of different concentrations,

can be operated.

  A variant of this second calcination method may consist in carrying out the heat treatment of the IM-5-P zeolite containing the organic structuring agent, at a temperature generally between 500 and 850 ° C., optionally and preferably in the presence of water vapor. . In this case, the stages of calcination of the organic structuring agent and dealumination of the framework are carried out simultaneously. Then, the zeolite is optionally treated with at least one aqueous solution of a mineral acid (for example HNO3 or HCl) or organic (CH3CO2H for example). Finally, the solid thus obtained can optionally be subjected to at least one ion exchange with at least one NH4NO3 solution, so as to eliminate practically any alkaline cation, in particular sodium,

  present in cationic position in the zeolite.

  The IM-5-P zeolite according to the invention is at least partly, preferably practically totally, in acid form, that is to say in hydrogen form (H +). The Na / T atomic ratio is generally less than 10% and preferably less than 5% and so

  even more preferred less than 1%.

  The invention also relates to a catalytic composition. It can comprise a) from 0 to 60%, for example from 0.1 to 60%, preferably from 4 to 50% and even more preferably from 10 to 40% by weight of at least one zeolite other than the phosphorus zeolite according to the invention and preferably zeolite Y of faujasite structure, b) from 0.1% to 97%, preferably from 0.05 to 40% and even more preferably from 0.1 to 20% d '' at least one IM-5-P zeolite at least partly in hydrogen form, having the characteristics given above and, c) at least 3% of at least one matrix, and preferably at least 20% and by

example 40 to 70%.

  According to a first variant, this composition can contain the zeolite according to the invention

  associated with at least one matrix of inorganic oxides.

  According to a second variant, this composition can comprise at least one IM-5-P zeolite, at least one matrix already mentioned and at least one zeolite other than the

IM-5-P zeolite.

  For example, in the case of the use of the catalytic composition in catalytic cracking in a fluidized bed, this zeolite will be a cracking zeolite such as a Y zeolite which comprises the ultrastable Y zeolite (modified and vapor stabilized), the zeolite X,

  Beta zeolite, ZSM-5 type zeolites, silicalites, LZ 210 type zeolites.

  This usually amorphous or poorly crystallized matrix is chosen for example from the group formed by alumina, silica-alumina, silica, magnesia, clay, titanium oxide, zirconia, combinations of at least two of these compounds and combinations

alumina-boron oxide.

  The matrix is preferably chosen from the group formed by silica, alumina, magnesia, silica-alumina mixtures, silica magnesia mixtures and clays, the

kaolin and metakaolin.

  The catalytic composition used in particular in catalytic cracking of fillers

  hydrocarbons can be prepared by any method known to those skilled in the art.

  Thus, the composition can be obtained, for example by simultaneous incorporation of the IM-5 zeolite modified with phosphorus, at least in part in hydrogen form, and of zeolite Y according to the conventional methods for the preparation of cracking catalysts containing a zeolite. The IM5-P zeolite can be dealuminated or stripped of its metal T, at least in part. The composition can also be obtained by mechanical mixing of a first product containing a matrix and another zeolite? a Y zeolite for example, and a second product comprising the IM-5 zeolite modified by adding phosphorus, at least partially in hydrogen form, described above with a matrix which may be identical or different from that contained in said first product. This mechanical mixing is usually carried out with dried products. The drying of the products is preferably carried out by spray-drying, for example at a temperature of 100 to 500 ° C.,

  usually for 0, 1 to 30 seconds.

  After spray drying, these products may still contain about I to 30% by

  weight of volatile matter (water and ammonia).

  The catalytic composition thus prepared and used in cracking may contain: a) from 0 to 60%, for example from 0.1 to 60%, preferably from 4 to 50% and even more preferably from 10 to 40% by weight at least one zeolite other than the phosphorus zeolite according to the invention and preferably the zeolite Y of faujasite structure, b) from 0.10 to 97%, preferably from 0.05 to 40% and even more preferred from 0, to 20% of at least one IM-5-P zeolite at least partly in hydrogen form, having the characteristics given above and, c) at least 3% of at least one matrix and preferably at least 20% and by

example 40 to 70%.

  The general conditions of catalytic cracking reactions are particularly well known not to be repeated here in the context of the present invention (see

  for example the patents US-A-3,293,192, 3,449,070, 4,415,438, 3,518,051 and 3,607,043).

  In order to produce the greatest possible quantity of gaseous hydrocarbons with three and / or four carbon atoms per molecule, and in particular propylene and butenes, it is sometimes advantageous to slightly increase the temperature at which the cracking is carried out. , for example from 10 to 50 C. The catalyst of the present invention is however in the majority of cases sufficiently active so that such a temperature increase is not necessary. In very severe conditions of use to maximize the production of propylene, the contact time can be high: 10,000 to 60,000

approximately milliseconds.

  The catalytic cracking conditions can then be as follows: contact time between 10 and 60,000 milliseconds catalyst weight ratio on charge (C / O) between 0.5 and 50 15. reaction temperature 400 C at 800 C pressure 0, 5 to 10 bar (1 bar = 105 Pa)

  The following examples illustrate the present invention without, however, limiting its scope.

  Example 1: Preparation of the IM-5-P zeolite - Cracking of n-decane: The starting IM-5 sample was used in acid form and without structuring. The preparation is carried out in 5 steps: 1. The zeolite in powder form is dispersed in an aqueous solution in a container containing: * water (deionized) with a liquid / solid weight ratio = 10 g / g * X% by weight of phosphorus in the form of ammonium phosphate of chemical formula NIH4H2P04, X being the percentage of phosphorus targeted. For example, for 1 g of zeolite: - 1Og of water - 0.0375 * X g NH4H2P04. (purity equal to 99%)

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  2. The well dispersed mixture is placed in a rotary vacuum evaporator maintained at a temperature of 80 C. The pressure is adjusted so as to avoid boiling too much

  fast: the mixture must be dry after! about an hour.

  3. Dry in the oven at 100 ° C overnight.

  4. The dry sample is pelletized, ground and sieved to 0.59-0.84 mm. 5. The 5 samples of IM5 zeolite containing 0, 0.5, 1, 2, 3 and 4% by weight of phosphorus are finally calcined under 100% steam at 750 C for 5 hours (step

  hydrothermal also called steaming).

  Physico-chemical characteristics of IM-5-P: The crystallinity measured by X-ray diffraction (DRX) and the BET surface of 5 samples obtained after the 5 steps as well as the starting sample (fresh) are shown in the following table : IM-5-P DRX crystallinity Surface BE m2 'P content 0% fresh 100% 352

0.5 95.9% 285

l 91.0% 279

2 82.1% 267

377.3% 262

4 71.2% 231

  The DRX spectra of the 6 samples are very similar and show the lines

  characteristics of a sample of IM-5 described in the French patent application FR-

  2.754.809. In particular, samples containing phosphorus do not show any

  characteristic lines corresponding to the addition of phosphorus.

  The BET surfaces show that all the samples have a very good crystallinity which

  decreases slightly as the phosphorus content increases.

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  Example 2: Preparation of 6 catalysts with and without phosphorus and cracking of n-

  decane: The catalysts are prepared by mixing 0.5g of zeolite with or without phosphorus with 2.5g of silica SiO2 (BASF D-1 l-11). This silica was previously calcined at 800 C for 11 hours in air and its specific surface is then 97 m 2 / g. The 6 catalysts prepared with IM-5 zeolites containing 0, 0.5, 1, 2, 3 and 4% by weight of phosphorus are evaluated in a cracking test of n-decane at 500 C in a micro-unit

  test (MAT unit). The injection time is 60 seconds.

  For each catalyst, three experiments are carried out by varying the mass of decane injected (1.54, 0.906 and 0.77 g of n-decane). We have reported in the table below

  the first order kinetic constant calculated from the conversion results.

% P (ex-NH4H2PO4) k '* 10-2 (s-I)

0 1.55

0.5 2.22

1 3.65

2 5.4

3 4.33

4 1.85

  As we can see, the best results are obtained for a content of

  phosphorus between 2 and 3% by weight.

  Example 3: Cracking of diesel fuel in vacuum: Three catalysts are prepared for comparison in cracking of diesel fuel. For each of them, ultrastable Y zeolite (USY) with a crystalline parameter equal to 2.432 nm is used. Adding an amount of additive (matrix and zeolite) (ZSM-5 for comparison, IM-5 without phosphorus and IM-5 with 2% by weight of phosphorus prepared according to Example 1) such that the weight ratio "zeolite Y / additive "= 3. The Si / Ai ratios of ZSM-5 and IM-5-P are 20 and 12 respectively. Then, the catalysts are calcined under 100% steam (steaming) at 750 C for 5 hours. The total mass of catalyst used

  is 3 grams for each experiment.

  s In the table below, we have reported the main characteristics of the vacuum diesel used Density at 60 C 0.916

K-UOP 11.84

  Refractive index at 67 C 1.4932 Sulfur (% by weight) 2.7 Nitrogen (% by weight) 0.15 Conradson carbon (% by weight) 0.09 Aniline point (C) 76 Na (ppm) <0.05 Cu (ppb) 30 Ni (ppb) 30 V (ppb) <25 Fe (ppm) 0.5 Average molecular weight 405 Distillation curve (C) ASTM D1 160

% 400

% 411

% 425

% 449

% 489

  The performance of the three catalysts was evaluated by cracking the vacuum diesel oil at 520 C. For an injection time of 30 seconds, the mass of vacuum vacuum diesel oil injected was 4, 3.5, 3, 2.5 and 2 grams while the mass of catalyst remains constant and equal to 3.0 grams. The conversion is given as being equal to 100 - (% LCO +% suspension) The values given in the table below correspond to yields expressed in% by weight. These are extrapolated values obtained for a conversion of approximately 60%. Catalyst ZSM-5 IM-5 IM-5/2% P Dry gases 3.8 3.1 2.1

LPG 21.9 19.1 16.8

  Petrol 29.6 33.6 34.2 Coke 6.5 6.2 4.3 Conversion 61.8 62.0 57.4

LCO 6.9 7.2 10.5

Suspension 31.3 30.8 32.1

C3 = / C3 1.2 1.4 2.2

C4 = / C4 0.4 0.5 0.8

  As we can see from this table, the addition of phosphorus significantly reduces the yield of dry gases (H2, Ci and C2) and coke while the

  contents of light olefins C3 and C4 are markedly improved.

Claims (11)

Claims   1. IM-5-P zeolite with phosphorus comprising silicon and at least one element T chosen from the group formed by AI, Fe, Ga, Ti and B and containing at most 10% by weight phosphorus.   2. Zeolite according to claim 1, in which the phosphorus content is at most   equal to 5% by weight of the zeolite.   3. Zeolite according to claim I or 2, in which the atomic ratio Si / AI is at   less equal to 5 and preferably between 20 and 400.   4. Zeolite according to one of claims 1 to 3, at least in part in its form   hydrogen. 5. Process for the preparation of the IM-5-P zeolite with phosphorus according to one of   Claims 1 to 4, in which a suitable impregnation is impregnated with   IM-5 zeolite possibly calcined, with an aqueous solution of at least one acid chosen from the group formed by H3 PO3, (NH4) 3 PO4, (NH4) 2 H PO4, (NH4) H2 P04   or one of its salts and the product obtained is calcined at a temperature of 350 to 1000 C.   6. Process for the preparation of the IM-5-P zeolite with phosphorus according to one of claims 1 to 4, in which at least one organic cation is brought into contact   nitrogen containing at least one silicon or germanium oxide, at least one metal oxide T chosen from the group formed by AI, Fe, Ga Ti and B and at least one phosphorus compound and optionally an alkali metal oxide M and / or ammonium, or their precursors, the mixture generally having the following molar composition XO2 / T203 at least 10, (R1, n) OH / XO2: from O, O 1 to 2 H2O / XO2 from 1 to 500 Q / XO2: from 0 .005 to 1 LqZO2: from 0 to 5 22 2794116   o X is silicon and / or germanium, R is a cation of valence n which includes M (an alkali metal cation and / or ammonium), and / or Q (a nitrogenous organic cation or a precursor of that -ci or a decomposition product thereof), and LqZ is a salt, Z being an anion of valence q and L an alkali metal or ammonium ion which may be similar to M or a mixture of M and a another alkali metal ion or an ammonium ion necessary to balance the anion Z, Z possibly comprising an acid radical added for example in the form of an L salt or an aluminum salt. 7. The preparation method according to claim 5 or 6 wherein the IM5-P zeolite is   partially freed of metal T by the direct acid attack method.   8. Preparation process according to claim 5 or 6 wherein the IM5-P zeolite is partially rid of the metal T by the method of heat treatment and acid attack.   9. Preparation process according to one of claims 7 or 8 wherein the heat treatment is carried out in the presence of water vapor.   10. Catalytic composition comprising at least one IM-5-P zeolite with phosphorus   according to one of claims 1 to 4 at least partially in acid form, at least   a matrix and optionally at least one zeolite other than said IM5-P zeolite.   11 1. The catalytic composition according to claim 10, in which the weight percentages are as follows: a) from 0 to 60%, for example from 0.1 to 60%, preferably from 4 to 50% and even more preferably from 10 to 40% by weight of at least one zeolite other than the IM-5-P zeolite and preferably the Y zeolite of faujasite structure, b) from 0.01 to 97%, preferably from 0.05 to 40% and even more preferably from 0.1 to 20% of at least one IM-5-P zeolite at least partly in hydrogen form and, c) at least 3% of at least one matrix, and preferably at least minus 20% and by example 40 to 70%.   12. Preparation of the catalytic composition according to one of claims 10 and 11 by   mixture of the matrix and possibly of a zeolite other than IM-5-P with the said IM5-P zeolite.   13. Use of a zeolite according to one of claims I to 4, 10 and 11 or prepared   according to one of claims 5 to 9 and 12 in a catalytic cracking process of a hydrocarbon feed.   14. Use of a zeolite according to claim 13 in a catalytic composition   comprising a cracking catalyst other than said zeolite.